1. Field of the Invention
The present invention relates to a data accessing method and system, and particularly relates to a system including master and slave devices.
2. Description of the Prior Art
FIG. 1 is a block diagram illustrating prior art writing operations between master devices and slave devices. As shown in FIG. 1, master devices include a master device 101 and a master device 103, and slave devices include a slave device 105 and a slave device 107. The master device 101 includes a processor that can process less data each process cycle (for example, 24 bit), and the master device 103 includes a processor that can process more data each process cycle (for example, 32 bit). Also, the slave device 105 can access less data each process cycle (for example, 24 bit), and the slave device 107 can access more data each process cycle (for example, 32 bit). The master device 101 and the master device 103 can respectively write data to the slave device 105 and the slave device 107, as indicated by the arrows shown in FIG. 1. However, since the empty space of the slave device can not be filled with blank data or null data and all data received by the slave device must be data having meanings, some problem will happen if a master device writes data less than the data amount that a slave device can receive each process cycle to the slave device. For example, the master device 101 writes 24 bit data to the slave device 107.
FIG. 2 is a block diagram illustrating prior art reading operations between master devices and slave devices. Similar with FIG. 1, master devices in FIG. 2 include a master device 201 (24 bit) and a master device 203 (32 bit), and slave devices include a slave device 205 (24 bit) and a slave device 207 (32 bit). The master device 201 and the master device 203 can respectively read data from the slave device 205 and the slave device 207, as indicated by the arrows shown in FIG. 2. However, a problem will develop if a master device reads more data than the data amount the master device can process each process cycle. For example, the master device 201 reads 32 bits data from the slave device 207.
Therefore, a new data accessing method and a system utilizing the data accessing method is needed to solve the above-mentioned problems.